Pressure gauge



A. B. LOW.

PRESSURE GAUGE.

APPLICATION FILED AuG.4. 1921.

Patented July M, 1922.

WITNESS.

ATTORNEYS.

verinnern n. Loiri, es DENVER, COLORADO.

rizlissrrah Genti-n.

peciicaton of 'Letters "Patent .rafentedaeiy ii, 192e.

application inea august i, i921. siai in. s'a's.

to be understood that the improved article l inay be used also, shouldoccasions arise, in

other relations where a pressure chamber provides .a suitable lnippleand stem contr'dlled valve therefor.

The primary aim oi' the invention has been to dey e such "a pressuregauge that Wil?, not only fulfill lall ot the requirements demandedtliereo'l', but which also 'i's of com- `paratirely small dimensions andWith a niiniinuin nu mb'er ot' 'cooperating parts little liable get outot 'order or "otherwise improperly Tunction, one which isAself-contained vwith smoothly linished and ornateeX- terior, and whichas a whole'is so compact as to occupy Vinco'nsequential space whenstored in the pocket or otherwise.` v

iin 'an earlier )at'en't. l\lo. 1392587 'ot Oct. 4t. 1921', lharcrd'isclosed a pressure gauge wherein a tubular indicator or `gaugebar is normally supported loosely upon va piston having a 'guide stem,with a coiled spring also supported byV said piston, in encompassingassociation .with said gauge bar and guide stem. and winch coiled spring1n turn mounts a retaining washer held seated thereby at the upper Yendof the casingin yielding irictional engagement with said tubu-4 larindicator. all or" which elements function as therein set forth, but 1nthat case the coiled spring` is normally distended and is oit asubstantial length compressed upon the ascent ot the piston.

In the present case7 although somewhat analogous to the deviceaforesaid, there has' been a substantial rearrangement of the elements.including the' disposition and V.mounting oit the gauge bar retainingmeans and the provision fot' a normally compressed coiledspring that isdisposed below the pistou element, which coiled spring is distend'eflupon thc ascent ot the piston element, so that I am tlnis enabled toemploy "an exceeding@ 'iight rti'actilspnngfcoin- .pafrat i vel-y short'length.

lin addition 'to the foregoing 'fe'a`ti'irs, the

'conilpaic'tness tlie device, its simplicity in assembling andoperation, and the coinpaiativey 'shiall cost of manufacturing andinarl'eting the saine, other rodojecltfs and advantages will `be"apparent Las 'incidental `to the ltolloirii'i'g'g disclos` land withthese gneia'cing remarks inference Will non7 be 'had to the accompanyingdrawings, illustrating f een embodiments di in@ improvements, in whichdrawings-"- Figure i is a longitudinal sectional 'View 'through thedevice as lit appears when not in use, the section 'being taken along'the piane ai@ une 142 0f ing. a, the inusuation being on 'a "g atlye'xag 'rated scale;

rFigure 2 is a substantially "aii'alog'ous View, but with the pistonshown as being retracted, ivhile `the gauge 'bar is maintained el'evtuedm set position for reading, when the device has been applied "in use anddetached; Figures 3 and el are top and 'bottom plan vietts asrespectively indi'c''lted by the arrows 3 and 4f: Figures 5 and 6 aretransverse secliona-l views taken, respectively, along the tplanes ofthe lines 5' 5 and 6 6 of Fig. 2; 'and YFigure 7 a View substantiallyanalogous to Fig. 42 but illustrating a slightly inodiiied construction.Y

i0 'designates the casing, providing an open-ended linrg'itudinalchamber il therethrough which imay be internally threaded at one end, as'at 12, While its other end is smooth 'and is restricted. as at 13, toconiorm with the cross-'sectional shape of the gauge bar.

In so tar as the 'instant improvements are concerned. t-he casing mightbe of other cross-section than shown, and in fact the casing l() and thechan'ib'erll might be prop vided 'for by an ordinary short tube section,

properly capp'ed at the top and plugged at the bottoni, but from othermore desirable aspects the chamberll is 'preferably formed as 'alongitudinal bore through an otherwise solid blank of light metal, suolias aluminum, o'lE the e'migated elliptical design 4as illusrated.. andbeing Vrounded off to form eX- terior top and bottom Jfaces otsubstantially conter; conformation, the whole providing an extremelyshort length casing that is not only of conveniently shaped design butYdiameter than the shank portion.

other forms adapted for the reception ofra Y gauge bar of other shapesin cross-section.

The plug closure for the threaded lower end 12 of the casing issubstantially the same as that described with reference to my patentaforesaid, and embodies an externally threaded base' disk 14 having aboss 15 formed on its inner face while its outer face provides a V.shankterminating in a contact head 16, of

less diameter than the base 14 but of greater All of these Y plugclosure parts are preferably formed integral, and a small axial bore 17extends therethrough and through the boss l5, opening at its innner endto the chamber 11, while at its outer end merging into a Aininutelyrestricted inlet bore 18 that in turn terminates in a diagonal groove orrecess 19, provided at vthe outer face of the head 16, which groove 19functions both as a passage for air to said inlet bore and as a meansfor receiving the end of a screwdriver, or anal- Y ogous implement forobvious purposes.

20 is a gasket of rubber, or other suitable substitute, centrallyapertured to fit over the shank portion between the disk 14 and the head16, and provides an outer seating face 21 surrounding but slightly insetfrom the head Y16,7it being understood that the head 16 serves as acontact means for engaging the projecting stem of an inflation valve,while the face 2l seats down snugly on the valve casing nipple toprevent any leakage ofpreSSi-ire, excepting the vescape into the gauge,when the inflation valve is opened by the-head 16. l

The bored nipple or boss 15 is transversely apertured to receive afastening' pin 22,

showny as a Vcotter pin, for attaching thelower end of the coil springelement later referred to, but this is primarily by way of illustrationonly as other fastening means may be satisfactorily employed.

Although fully explained in my patent aforesaid, it may be stated hereinthat the -objcct of making the bore 17 of greater diameter thanthelinlet bore 18. which is of about the diameter ofavery fine needle,is

.that should the inlet bore become clogged with dirt` the same wouldmost likely be blown clear by the air pressure, or at any event could beremoved readily with a straw or other fine article, as the inlet bore 18onlyY extends a slight distance from the recess 19 before it merges intothe larger bore 17.

Within the chamber l1. and normally disposed immediately above the 'plugclosure, lthere is located a piston element, shown at Figs. 1 and 2embodying an elongated downwardly opening shell 23, which fits thechamber 11 withsuliicient snugness to prevent undue pressure leakagetherearound while freely sliding therein, and this elongated pistonshell provides a closed top wall 24 that may be centrally apertured toreceive a rivet element comprising ahead 25, a shank 26 and a reducedterm1nal'2.

l/Vhen the rivet shank'is inserted through the apertured top wall of thepiston shell, the lower end of the shank proper is peened over, as at28, yup against the underneath face of the shell vtop, thus securelyfastening the saine,v while the reduced terminal 2 7, which may belikened to a flattened teat, projects substantially within the shell andis transversely apertured to receive the upper hooked end 29 ofaretractile coil spring 30, the lower end 31 of which is anchored to theplug closureV as by hooking over the transverse pin 22, of the hollowboss 15, withthe preferred means for attaching the spring Y ends, it isobvious that other attaching means might be employed, but at any eventit will be noted that the spring is of a diameter only a trifle lessthan the approximate diameters vof the piston shell and chamber 11whilethe length of the spring normally in its compressed state issuch as tobe wholly encompassed within the piston shell,as in Fig.v 1. The spring,therefore, may be formed of comparatively light resilient wire of manyconvolutions, which not only vaids the efficiency of the spring butprolonge its life as to efficiency.

32 indicates the gauge bar, having the Y pressure indicating scale face33, the upper portion of which operates through and is guided by the.slot 13, while the lower end` has a reduced terminal or neck 34, aroundwhich fits a washer 35, of leather, felt, cork or any satisfactorymaterial, held in place by the upper and lower metal disks 36 and 37,respectively,v the outer end of the neck 34 being finally peened over asat 38, holding all of these parts fiXedly secured. Obviously, however,it would be an equivalent if 38 was the head of al stud screw associatedwith a threaded bore in the neck 34.

The washer 35 serves dually both as a guide for the lower end of thegauge bar and as a retaining means to maintain the gauge bar in setposition for reading, when elevated bythe operating pressure being iooMaaate 'normal position by manual manipulation after the piston has beenretracted by its coil springO. Thus the gauge is a registering one,which be read after the gauge has been removed from association with thetire the internal pressure of which is being tested. rlChe washer 35being substantially snug-fitting, however, it would doubtless bedesirable to provide at least one small airrelieving aperturetherethrough, as would be indicated at` 35X of Fig. 5, or a verticalperipheral groove which would be its equivalent, to prevent any tendencytowards the trapping of cushioning air in the space between the washerand the piston element.

ln the slightly modified form shown at Fig. 7, the saine referencenumerals have been employed to indicate the same parts as heretoforedescribed, but in this form of `device the elongated pistonV shell 23,of the other figures, is substituted for by an equivalent althoughslightly different arrangement.

ln this view 89 indicates a piston guiding head that may be cylindricaland solid, and which provides a central depending stud A() thatterminates in the flattened teat 41. A downwardly disposed cupped pistonwasher 43, of suitable leather or analogous substance, is centrallyapertured to lit over the stud 10, and is firmly seated up against theunderneath suiface of the piston head 39 by a metal washer or disk del,that in turn is held in place by peening over the shoulder, as at 45,that is formed by the end of the stud proper where it merges into thereduced terminal or flattened teat 4l. Obviously, a stud screw asheretofore referred to,but with the terminal teat 41, would serve thesame end of fastening the cupped piston washer in place. The element lllis apertured transversely, as will be understood, to receive the springhook end 29.

The operation of the device will be selfevident but may be brieflysummarized as :follows z-VVhen the gauge is associated with the nippleof an inflation valve casing, the contact head 16 engaging theprojecting end of the stein of the valve will open the latter, while theface 2l of the gasket 2O seats down snugly on the top edge of the valvecasing, whereupon the pressure air in the pneumatic tire will escapeonly into-the gauge casing below the piston element thereof by way of fthe conduit 19-18-17 and in operating the piston element upwardly,against the tension of the normally compressed spring 30, the pistonelement in turn will elevate the indicator or gauge bar 32. The nowdistended coil spring 30 will immediately retract the piston element,when the air pressure is relieved by the removal of the gauge from thetire valve, but the gauge bar itself remains set in lregisteringposition as at Figs. 2 and T, by the retaining guide washer or' element35 in yielding frietional engagement with the wall of the chamber ll,until forced down again by external means. Of

' coiirse, itis understood that the coil spring jis proportionately`tensioned relatively to the indicator scale to properly register theair pressure.

' Having thus fully disclosed my invention, it will nevertheless beunderstood that l do not wish to limit myself unnecessarily to the exactdetails of construction as shown and described, excepting as they maycome within the terms of the ensuing claims or a fair interpretationthereof, viewed in the light of the specification if necessary. lWhat ldo claim as new and patentable is l. A pressure gauge of the characterdisclosed, embodying a casing that provides a longitudinal chamberopening to a top guiding aperture and having a bottom closure providedwith a duct therethrough and including a valve stem contacting elementand a surrounding seating face, an elongated indicator operating at itsouter end through said top guiding` aperture and towards its inner endprovided with a combined centering, guiding and retaining elementslidingly associated with the wall of said chamber in yieldingfrictional Contact therewith, actuating means adapted only for outwardlyoperating said indicator with its retaining element by pressure fluidadmitted through said duct, and retractile means for said actuatingmeans.

2. A pressure gauge of the character disclosed, embodying a casing thatprovides a longitudinal chamber opening to a top guiding aperture andhaving a bottom closure provided with a duct therethrough and in cludinga valve stem contacting element and a surrounding seating face, anelongated indicator operating at its outer end through said top guidingaperture and towards its inner end carrying a combined centering,guiding and retaining washer of yielding material frictionally engagingthe wall of said chamber, a piston element freely interposed betweensaid duct and indicator for actuating said indicator and its retainingwasher, in an outward direction only, by pressure fiuid admitted throughsaid duct, and retractile means for said piston element.

3. A pressure gauge of the character disclosed, embodyinga casing thatprovides a longitudinal chamber opening to a top guiding aperture andhaving a bottom closure provided with a duct therethrough and includinga valve stem contacting element and a surrounding seating face` anelongated indicator operating at its outer end through said top guidingaperture, into registering position, and towards its lower end carryinga combined centering, guiding and retaining washer of yielding materialfrictionally en- ,la'gingthe wall of said chambera piston lement in gardchr-Lumber, operntlvely asso elated wlth said duct and freely lnterposedwith reference to said indicator, for actuat-` ,piston element providing:l hollow interior with aclosed top ,and a downwardly opening bottom7and a normally Compressed coil l0 s rngd'sposed in the lower end of saidc lalnbelahd connecting saidV piston element with the lower end ofsadcasing.

In testimony -whereof, li aHX my signature.

' ARTHUR, B. Low.

